1. Field of the Invention
The invention relates to an apparatus for adjusting the toe angle of a wheel, and more particularly, to an apparatus capable of adjusting the wheel toe according to the travelling condition of a vehicle so as to improve the controllability of the vehicle.
2. Description of the Related Art
A car body of an automobile is supported by suspension elements to which wheels are attached. These suspension elements are variously devised to improve stability during travelling.
For example, as disclosed in Japanese Patent Public Disclosure (KOKAI) No. 15345/80, the caster, chamber and toe angle in the suspension for a front wheel are set to proper values in order to improve the controllability in steering. Thus, the vehicle performance may be adequate with respect to straight line stability, while it may smoothly make a turn. The front wheels also may return naturally to the straight drive position after turning.
However, in order to improve controllability during high speed travelling of the vehicle, it is necessary to improve the straight line stability of the vehicle, which is contradictory to the controllability in turning. Therefore, an apparatus for setting a rear wheel to toe-in has been proposed (for example, as shown in Japanese Patent Public Disclosure (KOKAI) No. 214470/83). Thus, the straight line stability during high speed travelling of the vehicle may be improved.
According to the apparatus noted above, however, problems are encountered since the structure of the apparatus is complicated, and the unsprung weight is increased since the apparatus is provided on an arm portion for supporting the wheel.
A steering gear of a vehicle described in the Japanese Utility Model Public Disclosure (KOKAI) No. 15051/85 relates to an apparatus for steering a wheel of a vehicle provided with two suspension arms extending widthwise of a car body and a carrier connected to respective outer ends of the suspension arms for supporting the wheel. The apparatus includes an arm to which an inner end of one of the suspension arms is pivotably connected about a horizontal axis, the arm being movable in the lateral direction of the car body, and an actuator for moving said arm. An inner end of the other suspension arms is pivotably connected to the car body about the horizontal axis.
Since the steering gear has one inner end of one of the suspension arms pivotably connected to the arm only about the horizontal axis, that is, the inner end of said arm moves two-dimensionally, an adjusting range of the toe angle of the wheel is relatively small.